diff --git a/gallery_dl/postprocessor/exec.py b/gallery_dl/postprocessor/exec.py
index f4aa971c..206dd56e 100644
--- a/gallery_dl/postprocessor/exec.py
+++ b/gallery_dl/postprocessor/exec.py
@@ -11,24 +11,29 @@
 from .common import PostProcessor
 from .. import util
 import subprocess
-import shlex
+import os
+
+
+if os.name == "nt":
+    def quote(s):
+        return '"' + s.replace('"', '\\"') + '"'
+else:
+    from shlex import quote
 
 
 class ExecPP(PostProcessor):
 
     def __init__(self, pathfmt, options):
         PostProcessor.__init__(self)
-
         args = options["command"]
 
         if isinstance(args, str):
-            self.args = util.Formatter(args.replace("{}", "{_temppath}"))
+            if "{}" not in args:
+                args += " {}"
+            self.args = args
             self.shell = True
             self._format = self._format_args_string
         else:
-            for i, arg in enumerate(args):
-                if "{}" in arg:
-                    args[i] = arg.replace("{}", "{_temppath}")
             self.args = [util.Formatter(arg) for arg in args]
             self.shell = False
             self._format = self._format_args_list
@@ -37,19 +42,19 @@ class ExecPP(PostProcessor):
             self._exec = self._exec_async
 
     def run(self, pathfmt):
+        self._exec(self._format(pathfmt))
+
+    def _format_args_string(self, pathfmt):
+        return self.args.replace("{}", quote(pathfmt.temppath))
+
+    def _format_args_list(self, pathfmt):
         kwdict = pathfmt.kwdict
         kwdict["_directory"] = pathfmt.realdirectory
         kwdict["_filename"] = pathfmt.filename
         kwdict["_temppath"] = pathfmt.temppath
         kwdict["_path"] = pathfmt.realpath
-        self._exec(self._format(kwdict))
-
-    def _format_args_list(self, kwdict):
         return [arg.format_map(kwdict) for arg in self.args]
 
-    def _format_args_string(self, kwdict):
-        return self.args.format_map(_quote(kwdict))
-
     def _exec(self, args):
         retcode = subprocess.Popen(args, shell=self.shell).wait()
         if retcode:
@@ -61,18 +66,4 @@ class ExecPP(PostProcessor):
         subprocess.Popen(args, shell=self.shell)
 
 
-def _quote(kwdict):
-    """Create a copy of 'kwdict' and apply shlex.quote to its string values"""
-    kwdict = kwdict.copy()
-    for key, value in kwdict.items():
-        cls = value.__class__
-        if cls is str:
-            kwdict[key] = shlex.quote(value)
-        elif cls is list:
-            kwdict[key] = shlex.quote(", ".join(value))
-        elif cls is dict:
-            kwdict[key] = _quote(value)
-    return kwdict
-
-
 __postprocessor__ = ExecPP